微结构表面微重力下沸腾换热及临界机理研究

Investigation of Boiling Heat Transfer Performance and Mechanism of Critical Heat Flux for Micro-structured Surface Under Microgravity

本文研究了微重力下新型复合微结构表面在FC-72溶液中的池沸腾换热性能,测试了三种不同热流密度下该表面的温度变化趋势及气泡动力学行为,重点分析了高热流密度下沸腾临界现象。实验结果表明:复合微结构表面在中低热流密度下壁面温度和沸腾换热系数与常重力工况基本保持一致无明显恶化;在高热流密度下进入微重力后壁面温度仍能维持短时间稳定,直到整个换热面被气泡覆盖后壁面温度才开始上升直至临界发生。复合微结构表面独特的微结构阵列及沟槽结构增加了换热表面的毛细芯吸力,可有效提升沸腾过程中工质的补液速率从而提高临界热流密度。

The pool boiling heat transfer performance of bistructured surface based on micro-pinfinned structure was experimentally studied in FC-72 under microgravity.The changing trend of wall temperature and bubble dynamic of three different heat fluxes were detected,and the boiling phenomenon at boiling crisis was also analyzed.The experimental results show that at mid-low heat fluxes the wall temperatures and heat transfer coefficients are the same as under normal gravity.At high heat flux the wall temperature can maintain stable while entering microgravity until the heating surface is totally covered by a huge bubble.The bistrcutured surface has a strong capillary wick effect owing to its special microstructures and grooves,which can efficiently improve the velocity of liquid supply and enhance the CHF(Critical Heat Flux).